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(No Modem 2 SheetsSheet 1. B. G. MARTIN.

OUT-OFF VALVE. No. 313,089. Patented Mar. 3, 1885.

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2 SheetsSheet 2. B. G. MARTIN.

GUT-OFF VALVE.

.No Model.)

Patented Mar. 3, 1885.

UNrirEn dramas PATENT @rricn.

BENJAMIN GREEN MARTIN, OF CORK, IRELAND.

CUT-OFF VALVE.

SPECIFICATION forming part of Letters Fatent No. 318,089, dated March 3, 188 5.

Application filed July 10, I884. (Nomodel To all whom it may concern:

Be it known that I, BENJAMIN GREEN MAR- TIN, a citizen of the United States of America, residing at South Mall, in the city of Cork, Ireland, engineer, have invented a new and useful Out-OE Valve for Steam-Engines, of which the following is a specification.

The object of the invention is to increase the efficiency of equilibrium-valves of steam-engines by constructing the improved valve so that the steam may act with equal pressure on opposite sides of that valve, enabling that valve to move on equal balance of steampressure, and thereby reduce frictional resistance.

The improved valve consists of two cylindersan outer one and an inner onethe outer one being bored to receive the inner one. The inner tube is turned on the outside so as to accurately fit the bore of the outer cylinder at those parts where the steam and exhaust ports are situated.

Figure 1 is an under side view, and Fig. 2 is an external view, of the outer cylinder, with ports A A one or more, at each end, opening into two chambers, Nos. 1 and 3, situated upon the outside of said cylinder, and which are placed in connection with the passages leading to the two ends of the cylinder of the steam-engine, and also having an exhaustport, F, opening into achamber, No. 2, which is connected with the passage leading to the exhaust-pipe 0. Fig. 3 is an external view, and Fig. 3 an end view, of the inner cylinder shown in Fig. 4. Fig. 4 is a sectional view of the inner cylinder (which forms the valve proper) and of the outer cylinder, (which is usually the valve-case.) Fig. 4; shows by diagram the external surface of the inner valve laid out. Figs. 5 and 6 show the two ends, respectively, of the outer cylinder. Fig. 7 is an end section of the inner and outer cylinders shown in Fig. 4.

The cylinder or case I, containing the three chambers Nos. 1, 2, and 3, may be cast together with the outer cylinder of valve orvalvecase, or with the steam-engine cylinder, or separately from both, as may be'found most convenient for attaching the improved valve to old or existing steam-engines.

The two ends of the outer cylinder (shown,

respectively, by Figs. 5 and 6) are fitted with detachable heads no 00. On either or both of these heads is provided a stuffing-box and gland, and also a steam-pipe connection, N, Fig. 5. This inner cylinder has three steamcompartments, D D E, of which D D are the live-steam compartments, and the center compartment, E, is for the exhaust-steam. These compartments or chambers for steam are separated by partitions LL, of suitable forn1,Which may be sloping, stepped, straight, or other suitable shape or form according to the shape and position of the ports used. 1

The two live-steam compartments D D have suitably-shaped ports A A, which may be of a rectangular, rhomboidal, or triangular figure for the admission and cut off of steam to the steam-engine cylinder through the ports A in the outer cylinder and chambers 1 and 3 in the case attached to it. and the center or exhaust compartment. E, has suitably-formed ports B B, which may be oblong, square, sloping, or otherwise adapted to the parts they operate with, for the exhaust-steam to pass away through from chambers 1. and 3 of the case on outer cylinder into the exhaust-steam chamber E, and thence through ports M M into the chamber No. 2 in the case or outer cylinder, and then away to a condenser or the atmosphere by pipe 0, Figs. 1 and 2.

The steam and exhaust ports A A and B B may be formed in the belts of the cylinder or valve containing the partitions, but facing opposite sides of those partitions, so that by the revolution or oscillation of the cylinder these ports may be alternately brought opposite the ports in the outer cylinder or valve-case. A crosshead, K, is castin or fitted to one or both ends of the inner cylinder, to which a rod, J, is attached, and this rod passes through the stuffi ing-loox G. When only one steam-pipe is used or connected to the outer cylinder, Fig. 1, a

steam-pipe, 0, passes from one live-steam compartment of the valve to the other through the exhauststeam compartment E. This pipe 0 allows the steam to pass from one live-steam compartment to the other where steam is fed into one compartment only, as is the case when only one steam-pipe connection is used on the outer cylinder, Fig. l, and consequently the pressure of steam in each live-steam compartment is the same as it would be if both ends of the cylinders were in communication with the steam pipe or boiler, and consequently the pressure on each of the partitions which separate the live-steam compartments from the exhaust-compartment is also equal, and being in opposite directions, the pressure of steam upon the valve is balanced or the valve is in equilib rium. The inner cylinder, Fig. 4, may have a packing ring or rings, aV groove or grooves between each live-steam compartment and the exhaust-compartment, and also'between each livesteam port and exhaust-port to prevent steam leaking from one to the other. D (see Fig. 3) is the live-steam compartment. E is the exhaust-steam compartment; 0, the steampipe from one live-steam compartment to the other. A A are the steam-ports.

The motion to be communicated from the crank-shaft of the steanrengine to the inner cylinder through the rod J may be a rotary, an oscillatory, or a reciprocating movement, according to the arrangement of the ports and the form of ports adopted.

Gearing communicating to the rod J, and thereby to the inner cylinder, may give a rotary movement whereby steam may be admittedto and be exhausted from the steam-engine cylinder, and at the same time admit of the rod J moving longitudinally through the stuffing-box, and therehygive the innereylinder a movement in a direction transverse to 'the ports in the outer cylinder for the purpose of varying the point ofcut-ofi' of the steam and the ratio ofe'xpansion, this longitudinal movemeut being actuated and controlled by the governor or by hand-gear.

Should an oscillating movement be preferred to a rotary one for the inner cylinder, a like arrangement ot'cut-off may be used, the ports in the inner cylinder being formed of a rhomboidal form instead of triangular, such triangular form being found well adapted when employing a rotary movement.

Having thus described and ascertained the nature of-my said invention and in what man ner the same is to be performed, I hereby declare that what I claim is -The describedconstruction or arrangement of parts forming a valve for the control or regulation of the steam supplied to steam-engine cylinders, said valve consisting of an in ner cylindrical body or part divided into steam and exhaust chambers by dividing-walls, and provided with suitably-shaped apertures or ports l'or"passage of steam, the steam-chambers being connected by a passage, and of an outer cylindrical case or cover, also provided with suitable passages or ports adapted to opcrate with those of the inner cylinder or valve proper, substantially as shown and set forth.

In witness whereof I have hereunto set my hand this th day of June, 1884.

BENJAMIN GREEN MARTIN.

Witnesses:

JOHN J OYOE FOLEY, Solicitor and Notary, 86 South Zlfall, Cork.

OHARLEs J. CONROY, Solicitofis Assistant, 'Easons Hill, Cork.

JOHN MURPHY, Solicitors Assistant, 341 Blarney S11, Cork. 

